The present invention is for a means for power transmission, between a linearly moving mechanism and a rotationally moving mechanism. The invention is primarily intended to be used for combustion engines but is not limited to this field.
The transmission of power between a rectilinear movement and to a rotating movement usually takes place with the use of some kind of crankshaft or a like device. In some cases, however, crankshafts are less suitable, and this is especially the case when linear movements of different often opposite directions shall be transferred into a rotating movement. Especially this holds for the kind of power-machines, e.g. combustion engines, compressors and pumps where two pistons at the same time work against each other in a common cylinder bore. In such cases the use of crankshafts brings with it complicated mechanical designs necessary to convert the total power from the two pistons into one common rotating movement.
In a traditional crankshaft design there are forces between the piston and cylinder bore which cause so called chest drawer effects. In these designs the small end of the piston rod is positioned underneath the piston which brings with it a design which is very complicated from a manufactured point of view, and which sets special requirements for lubrication and the design of the lubricating system The other end of the piston rod is mounted in bearings on the crankshaft and frictional forces in this bearing reduce the mechanical efficiency of traditional designs. With the means of the present inventions the sideforces which cause the chest drawer effects are greatly reduced, and the need for lubrication is much reduced and the remaining need for lubrication is simplified. Further an essential reduction is achieved of the mass of piston and parts which correspond to piston rod, crankshaft and crank bearings and important simplifications are achieved by the manufacture of these parts.
The present invention is for a means to transmit power between a linear movement and a to a rotating movement by means of a ballbearing which runs in tracks. The means comprises a ball which is surrounded by a ballholder which is mounted onto a piston rod or corresponding means for each ball for transmission of the linear movement.
The balls are movable both with one (upper) part in linear tracks and with another (lower) part in a common closed curved track in a rotating disc. The combination of the linear tracks and the curved track holds the balls in position and makes it possible for them to move only in linear backwards and forward movements in the direction of linear tracks and with the inner and outer position respectively defined by the respective inner and outer distance of the curved track to the rotational centre of the rotating disc. The linear track and the curved track have a generally semicircular cross-section which closely follows the balls. Adaptation, tolerances etc. to the balls is decided in consideration of choice of material, rotational speeds, loads, lubricating means etc.
The curved track has a closed curved shape where the shape is decided by the movement of the balls relative to the turning angle of the rotating disc. The balls achieve a forward and backward linear movement if the curved track is designed with variable distance to the rotational centre of the rotating disc. If the curved track has a constant distance to the rotational centre circular shape, the balls will make no forward or backward movement. If the distance to the rotational centre is increased the balls move outwards, and if the distance to the rotational centre is decreased the movement is inwards. The number of forward and backward movements per round for the balls is thus due to the shape of the curved track. In desired segments the balls may be given a resting position if the curved track is given a circular shape. The number of forward and backward movements per rotational round for the balls is due to the number of respectively outer and inner track positions which the curved track reaches during a full round. It is not necessary that all of the outer and inner positions are varied. It may also be desired that they are non-rotational symmetric i.e. the balls do not make movements which are symmetric in respect of the rotational centre.
When turning of the rotating discs increases the distance from the curved track to the rotational centre the inside of the curved track forces the ball outwards. It is thus the one quarter sector of the great circle in the contact line between the balls and the curved track which forces the respective ball outwards. When the rotating disc turns so that the distance of the curved track to the rotational centre decreases the outer side of the curved track in the corresponding way forces the balls inwards. The balls are caused to move when the curved track thus changes its distance to the rotational centre. In these positions the curved track is at a non-right angle to the linear tracks. The components of force in the linear bearings caused by the above mentioned forces from the angled position of the curved track and transferred by the balls up to the linear bearings is split up in a force direction only along and across the linear bearings. It is the resulting force components in the length direction of the linear bearings which affects the ball and gives to them forward and backward motions.
The system for distribution of power with alternately working forces in various part sections around the ball and further distribution of the forces through the ball and out to the linear and the curved tracks respectively additionally has means for further introducing and transferring forces around the ball. From the rotational centre and out to the respective ball there is arranged a pressure round/piston round which runs inside the linear bearing up to the ball and is applied to the ball mainly in that part of the great circle sector which is turned inwards to the rotational centre and situated above the curved track. This sector of the ball can receive a force, transmit the force further through the ball to the quartersection of the great circle to that part of the curved track which is not at right angle.
The angled position causes counterforces in the linear track which are separated into force components along and across the linear track. The force component along the linear track causes a counterforce in the rotating disc having the curved track which in itself transmits a turning movement and force to the rotating disc. In a corresponding way an inwardly directing force from the curved track transmits itself through the ball, force components etc. up to a force which forces the pressure rod inwards towards the rotational centre.
In phase of operation when forces out from the ball shall be transmitted to (the pressure rod) the pull rod/the piston rod the force shall be transmitted mainly from that part of the great circle sector of the ball which is turned away from the rotational centre and situated above the curved track. From here the force shall be transmitted, pass the ball and into the connecting rod. This can be achieved in various ways by connecting above the tall or connecting at the sides of the ball which are situated in the lengthwise direction of the curved track.
The balls will rotate around their own theoretical axis of rotation, the direction of which is mainly continuously changing. The ball will have a direction of rotation which is mainly generated by friction from the curved track in its direction of rotation, but it will also be affected by friction from the linear track. If the design could be made without friction the ball should not at all have to rotate, but only make linear forward and backward movements, not rotating around its own theoretical axis of rotation. The balls will thus have both slipping and rotating functions, relative to both the rotating curved track and the linear track. However the balls will not take positions with directly reversing directions of rotation, but the ball is supposed to be continuously rotating and with a slipping function relative to adjacent pressure sector surfaces. When the ball also continuously rotates around its own axis of rotation the lubricant which is needed can also be introduced between the ball and the pressure sector surfaces in question. It is then important that the quality of the lubricant, its consistence etc. and the connecting of the pressure sector surfaces to the ball, the kind and quality of the ball are optimised and adapted to the actual application of the power machine equipment as far as loading, rotational speed, number of strokes per round, accelerating and retarding forces by reversing directions of the linear movement etc.